1. Field of the Invention.
The present invention relates to an improved internal combustion engine having a higher thermal efficiency than existing engines. In particular, the present invention relates to an improved internal combustion engine wherein the quantitative expansion of the charge during the power stroke is at least twice the quantitative compression of the charge during the compression stroke.
2. Prior Art.
Internal combustion engines using reciprocating pistons are well known. Pistons slide back and forth within cylinders and transmit power through a connecting rod to a crank shaft. Each cylinder has an intake valve for delivering a charge and an exhaust valve.
The traditional cycle for an internal combustion engine has a defined sequence of operations. An intake stroke draws a charge into a cylinder through its intake valve which is open. A compression stroke compresses the charge in the cylinder with both intake and exhaust valves being closed, raising the temperature and pressure of the charge. During a power stroke, ignition and burning of the charge takes place liberating energy and further raising the temperature and pressure of the gases. Pressure forces the piston downward with both valves closed. Finally, an exhaust stroke sweeps the cylinder free of the burned gases with the exhaust valve open.
Each stroke represents one-half of a revolution of the crank shaft or 180 crank degrees. Two revolutions of the crank shaft complete one cycle of the four strokes. A cam shaft is connected at a 1-2 ratio to the crank shaft and, therefore, revolves once each two turns of the crank.
Internal combustion engines operate by sustaining two nearly simultaneous processes: combustion whereby chemical energy is transformed into heat energy, and expansion of hot gases whereby heat energy is transformed into mechanical energy, work. Each process is relatively inefficient.
Early engines utilized valve timing where the intake valve would close during the intake stroke when the piston was at bottom dead center. It was discovered that engine power could be improved by lengthening the time that the intake valve was open. The intake valve was left open for a period of time after bottom dead center to take advantage of the inertia of the incoming fuel and air charge. Stretching of the intake valve timing allowed the cylinders to breathe deeper and take in a greater amount of fuel and air charge.
The ultimate object of these engines is to trap the greatest possible mass of fuel and air charge in the cylinders during the intake stroke to attain the greatest volumetric efficiency.
The present invention takes a diametrically different approach. The present invention utilizes a significantly smaller mass of fuel and air charge than the maximum possible mass of charge.
The present invention operates to transform more heat energy into work achieving a higher thermal efficiency using presently commercially available fuels.
A patentability search was conducted on the present invention and the following U.S. patents were uncovered.
______________________________________ U.S. Pat. No. PATENTEE ISSUE DATE ______________________________________ 2,344,993 A. Lysholm March 28, 1944 2,999,491 J. R. Harkness September 12, 1961 3,057,336 E. Hatz, Jr. October 9, 1962 3,416,502 J. Weiss December 17, 1968 3,540,424 Dietel November 17, 1970 3,919,986 Goto November 18, 1975 3,976,039 Henault August 24, 1976 3,986,351 Woods et al. October 19, 1976 4,033,304 Luria July 5, 1977 4,084,556 Villella April 18, 1978 4,174,683 Vivian November 20, 1979 4,192,265 Amano et al. March 11, 1980 4,232,641 Curtil November 11, 1980 4,261,307 Oldberg April 14, 1981 4,312,308 Slattery January 26, 1982 4,442,809 Nohira et al. April 17, 1984 4,484,543 Maxey November 27, 1984 4,485,780 Price et al. December 4, 1984 4,539,946 Hedelin September 10, 1985 4,572,114 Sickler February 25, 1986 ______________________________________
In Goto (No. 3,919,986) a third, additional valve is provided for a part of the charge to flow back into a suction pipe in order to control the output of the engine.
Dietel (No. 3,540,424) discloses variable release decompression valves for lowering compression. Henault (No. 3,976,039) discloses variable valve closings in order to adjust the richness of the charge. Woods et al. (No. 3,986,351) discloses third valves modifying existing engines to vary the timing. In Vivian (No. 4,174,683), a charge is controlled by intake valves designed to vary the inducted charge by closing variably either during the intake stroke or, alternatively, during different portions of the compression stroke.
Oldberg (No. 4,261,307), Slattery (No. 4,312,308), Maxey (No. 4,484,543) and Hedelin (No. 4,539,946) each disclose variable compression release valves.
Nohira et al. (No. 4,442,809), Curtil (No. 4,232,641), Amano et al. (No. 4,192,265) and Villella (No. 4,084,556) each disclose variable compression release valves wherein each valve releases a portion of the compression into an auxiliary chamber, the auxiliary chamber being used to assist in charging other cylinders.
Harkness (No. 2,999,491) and Hatz, Jr. (No. 3,057,336) both disclose a temporary compression release wherein the release is used to aid in starting the motor.
Lysholm (No. 2,344,993) suggests the desirability of decreasing the volume of charge but accomplishes this through a complicated procedure including restricting the charge inducted on the intake stroke by advancing closure of the intake valve.
None of the references suggest making only minimal modifications to designs of present internal combustion engines while achieving higher thermal efficiency than existing engines.
Accordingly, it is a principal object and purpose of the present invention to provide an improved internal combustion engine having higher thermal efficiency than existing engines without any change or upgrade of fuel.
It is a further object and purpose of the present invention to provide an improved internal combustion engine with less polluting emissions due to decreased use of fuel per unit of work.
It is a further object and purpose of the present invention to provide an improved internal combustion engine which may be constructed with only minimum modifications to existing internal combustion engines. Minimal design and tooling changes would be necessary, there being no additional parts or systems to add cost or complexity.
Additionally, it is an object and purpose of the present invention to provide an improved internal combustion engine emitting less noise than existing engines due to lower pressure upon opening of the exhaust valve at the beginning of the exhaust stroke.
A disclosure document relating to the invention was filed by the inventor on Sept. 25, 1986.